A majority of known valve actuators, especially for larger valves, suffer from significant wear of the mechanical part. For example, significant wear often occurs between a rotatable and user operable positioning element and a support member.
An example of such prior art valve actuator may be found in GB 2 206 185 which discloses a dispense tap for dispensing carbonated liquids. The dispense tap according to GB 2 206 185 includes a flow regulator which is operated when the tap is in an intermediate position between open and closed. The intermediate position is defined by a cam surface on the tap actuator.
It is a drawback of the dispense tap according to GB 2 206 185 that in order to achieve well-defined intermediate positions a relative high friction is required between the cam surface of the tap actuator and an underlying support surface. The high friction coefficient between the cam surface and the underlying support surface naturally introduces mechanical wear of the involved part. In particular, the underlying support surface will be highly exposed to wear over time.
It is an object of the present invention to provide a valve actuator offering less wear of the mechanical part.